tips on improving rendering performance?

I have a complicated rails screen with terrible performance.

I've been trying to narrow it down and figure out what is soaking up all
the time, but there doesn't seem to be any one major suspect...lots of
important stuff all taking up time.

The standard Rails logging shows that most of it is rendering time
rather than db time.

I've already gone through and removed most of the logging for the
production server, and it didn't make any noticeable difference.

Can anybody provide some suggestions for things they have changed that
made a big difference?

Also suggestions for good ways to chase this down? (so far I've been
just commenting out things one at a time trying to find "the culprit",
but as mentioned above, it seems like there are many rather than just
one or two.

Thanks!

Here have some tips, it’s in portuguese but is understandable;
http://www.slideshare.net/akitaonrails/caelum-dicas-web-2010